Hypermiling - Killing/starting engine in traffic.

[Aniviel]

Hello all. I've been reading about hypermiling (http://en.wikipedia.org/wiki/Hypermiler) and would like to know if it is safe/useful to use the autostop method in my Protege. This is where you shift into neutral, turn off the engine, and glide to a stop. (At, say, a long traffic light, thus eliminating a lot of idling, or down a hill, taking advantage of gravity.)

I've read about problems with flat-towing some types of cars and my first concern is for the health of my transmission. Apparently in some cases, the oil pump for the transmission is only in operation while the engine is on, and gliding while the engine is not engaged will wear on the transmission due to poor lubrication. Is this true of the Protege?

Secondly, I'd like to know how the Protege starts-- is there a significant amount of fuel injected upon turning the key? Or is this something that doesn't happen with modern fuel injectors? Obviously there's no point in saving gas while gliding if starting the car again is going to take up a lot of fuel.

Also, assuming the above works out in favor of this technique, will this effect significant wear on the ignition itself? How often is it safe to start and stop the engine?

Thanks for any information you can offer!
-Stacy.

[ProtoType5]

It's a bad idea...for all the reasons you stated plus...

It's not f-ing safe to do...

People have enough problem driving as is...don't go complicating it by worrying about "hyper-miling"

If you want better mpgs...don't drive..take the bus...ride a bike...or get a old Datsun diesel truck and run it with Fryer grease...

You will also loose most of your powered functions...ie braking and turning will become "non" powered...also, you run the HUGE risk of locking the steering, which can cause all kinds of problems...

[MP3Performance]

Assuming you have a manual transmission, if you are coming up to a red light or coasting to a stop you can just up-shift into a lower gear (ie 5th to 4th to 3rd and so on...) and let go of the gas. When you are in gear and with the foot off the gas the engine uses zero gas. This only works in gear because if you go into neutral then the engine automatically goes into idle.

[808MP5]

AGREED!!!


It's a bad idea...for all the reasons you stated plus...

It's not f-ing safe to do...

People have enough problem driving as is...don't go complicating it by worrying about "hyper-miling"

If you want better mpgs...don't drive..take the bus...ride a bike...or get a old Datsun diesel truck and run it with Fryer grease...

You will also loose most of your powered functions...ie braking and turning will become "non" powered...also, you run the HUGE risk of locking the steering, which can cause all kinds of problems...

[i like speed]

haha VERY bad idea. turning off the key while moving will lock the steering wheel. Not to mention the extra wear on your starter your not going to save any money even if you can keep from crashing.

[StealthWyvern]

Extremly stupid idea...

Its also against the law to coast downhill in certain states with the engine off.
What if some moron cuts you off?
What if the person infront you brakes hard?
what if you need to press the go pedal to avoid being hit?
What if the steering locks?

and the list goes on...

[red95_240sx]

nooo dont start doing that. fuq gas prices. just do what u do.

[IukekiniProtege]

http://www.youtube.com/watch?v=fbSjQfWjaO0 prime example of what could happen without the car on and going down the road, of course they were being towed, but see how the wheel can lock, and your brakes will not work nearly as good. its just a bad idea, and if you are concerned about gas mileage with a protege then you really shouldnt drive.

[Rockin03mp5]

Wouldn't the power brakes not work as well with the car off.

Very squishy.

[StealthWyvern]

Wouldn't the power brakes not work as well with the car off.

Very squishy.

You could still drop but gl with that. It woudl take like 4 times the distance to stop or something like that.

[Gasological]

All of the above stated reasons are very good. Also, the folks going 40 on the highway are below minimum speed limits and a safety hazard. If you're a rolling obstruction to highway traffic you're going to be in, or cause an accident eventually.

I'm hoping that this hypermiling fad is viewed with the same negative stigma as road rage soon, because it's stupidly unsafe, in just about all it's behaviors.

[dmention7]

Actually, rather than it being viewed as a fad, I would hope that automakers would take the techniques into consideration when designing next-gen cars. The practices may be unsafe when applied to vehicles not designed to be operated in that way, but if the car is designed specifically to use those practices then it would be perfectly safe and save gas. Granted, most of these are already designed into current hybrids, but hopefully the integration will be a little more widespread in the near future.


Also, I've always believed that hypermiling techniques are not inherently any more dangerous than what a lot of us euphemistically call spirited driving. As long as either is employed by someone with a good knowledge of what they are doing and with full regard of other drivers, they don't really introduce any significant danger. But someone with no experience in gliding and bumpstarting is pretty much on par with someone bombing freeway ramps without a working knowledge of their car's limits or behavior.

I mean really, someone shutting off their engine without knowing that the wheel will be normal when the key is at ACC, and locked when the key is at Off is about on the same level of noob as someone who doesn't know that a FWD car will tend to oversteer when pushed.

[red95_240sx]

at most u cud put ur car in neutral and roll, but so what? its not that big a deal

[i like speed]

Like was said in a previous post, If you're driving a manual and you're rolling in gear with no gas the car cuts fuel completely. If you're in neutral or have the clutch pushed in then it's idling which uses gas.

[red95_240sx]

oh word

[eagles453809]

wrong, the car still uses gas in gear regardless whether your foot is on the gas or not. if the motor is running guess what...its using gas. best way to get good gas is to be consistent with your gas pedal.

[red95_240sx]

oh so what i liek speed said isnt true??? i have auto anyway so...